Detergent compositions having



States atent DETERGENT COMPOSITIONS HAVING IMPROVED FOAM PERSISTENCE George 0. Funderburlr, Upper Penns Neck, N. 1., and Victor R. Hurka, Wilmington, Del., assignors to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application August 23, 1951, Serial No. 243,358

8 Claims. (Cl. 252152) This invention relates to detergent compositions of matter. It is an object of this invention to provide improved detergents, characterized by their ability to produce and maintain copious foam in the presence of greasy soil and by improved ability to emulsify such soil and hold it in suspension. Additional important objects and effects of this invention will appear as the description proceeds.

It is known that the power of a foaming detergent to emulsify greasy soil is related to its power to produce and maintain foam in the presence of greasy soil. The two practically go hand-in-hand, and the one may be taken as a convenient yard stick for the other. Thus, in household use, the housewife is accustomed to adding more detergent when foam disappears from the dishwater or washing machine. Among detergent manufacturers, this persistence of,foam in the presence of grease is spoken of as mileage" per unit of active component.

Accordingly, the principal problem in our invention is to endow common, commercial detergent compositions with the power to emulsify a maximum quantity of grease, and in so far as foaming is an index of this power, our problem is to produce a detergent which will continue to produce foam until a great many greasy dishes have passed through the washing bath containing the detergent.

Our invention is based on the observation that the primary alcohols obtained by condensing 1 mole of dodecyl alcohol (or a commercial grade of this alcohol, for instance lorol) with from 0.25 to 3 moles of ethylene oxide have excellent properties for increasing the mileage" of betaine type detergents, as more particularly set forth hereinbelow. Moreover, we have found that the percentage of this adjuvant which is effective on a given weight of the detergent may be varied within conviently wide limits.

More particularly, we have found that when the above mentioned mixture of primary alcohols, to which we shall hereinafter refer as the adjuvant, is added in quantity at least equal to 10% by weight of the active principle of the detergent, it will improve considerably the foam persistence in the presence of grease, in the case of the following betaine type detergents.

A. N-alkyl betaines, that is betaines having a long-.

chain alkyl group attached to the N-atom. This group may be expressed by the general formula /A1k HrC-N-CH:

O O CH:

wherein Alk designates a straight-chain alkyl radical of 10 to 16 C-atoms.

B. C-alkyl betaines, that is betaines having a longchain alkyl group attached to the C-atom of the betaine ring. The group usable in this invention may be expressed by the general formuladroxyethyl or hydroxypropyl.

For the purpose of measuring foaming persistence, a

special .test is detailed hereinbelow. This test is based on the quantity of grease required to be added to a detergent bath containing a specified weight of the detergent to be tested before the bath, upon agitation, ceases to. produce a stable foam. A composition of matter is considered as having satisfactory mileage if a 0.1% solution thereof (based on active ingredient) will produce a persistent foam when shaken in water con-' taining 5 gms. per liter of greasy soil. By the adjuvant of this invention, this tendency is increased in the sense that the foaming power will continue in the presence of larger quantities of greasy soil than are otherwise tolerable by the detergent.

The quantity of adjuvant required for good, practical results is at least 10% by weight of the active ingredient of the detergent composition, it'being noted here that most commercial detergents contain water and inorganic salts, usually sodium chloride and sodium sulfate, in addition to the active ingredient. Smaller quantities than 10% produce a correspondingly decreased improvement, but are nevertheless in most cases effective to a measurable degree.

Larger quantities of the adjuvant may be added, the upper limit being determined by the mutual solubility of the detergent and adjuvant. It must be explained here that the lorol-ethylene-oxide condensation products by themselves are not soluble in water. The detergent,'however, usually exerts some hydrotropic action upon this adjuvant and causes it to dissolve or disperse in the aqueous bath in quantities which may reach 100% or lgiglaer in the case of the alkyl betaines hereinabove de- Without limiting our invention, the following examples will serve to illustrate our preferred embodiments thereof. Parts mentioned are by weight.-

Example 1 Commercial C-cetyl-N-trimethyl betaine was mixed in in each case.

Grams of Standard Soil Required to Break Foa1n Percent Adjuvant Based on Weight of C-Cetyl-N-Trlmethyl Betalnc I In Dls- In Water 0! tilled p. p. m. Water Hardness Example 2 The experiments of Example 1 were repeated using as detergent C-decyl-N-trimethyl betaine. The results of the tests were as follows:

Grams of Standard Soil Required to Break Foam- Percent Adjuvant Based on Weight of Betalne In Dls- In Water at tilled 300 p. p. in.

Water Hardness 5 Nil Example 3 The experiments of Example 1 were repeated using as Grams of Standard Soil Required to Brnuk Foamlcrcent Adluvunt Based on Weight oi .Mm

Betuiuc In Dls- In Water nl tilled 300 p. p. in. Water Hardness Example 4 The detergent in this case was N-decyl-dimethyl betaine. This detergent was mixed, in a series of experiments, with several quantities of the condensation product obtained by reacting 1 mole of lorol with 1 mole of ethylene oxide. Tests of the type alluded to gave the following data:

Grams of Standard Soil Required to Break Fonm Percent Adjuvant Based on Weight of Betaine In Dls- In Water oi tilled 300 p. p. m.

Water Hardness Example 5 The procedure of Example 4 was repeated, using as detergent N-cetyl-dimethyl betaine. The data observed were as follows:

Grams of Standard Soil Required to Break Foam- Percent Adluvant Based on Weight of Betalne In Dls- In Water oi tilled 300 p. p. m.

Water Hardness 0 0 in n 30 100.0 80

Example 6 The entire set of experiments mentioned in Examples 1 to 5 was repeated, substituting for the adjuvant therein mentioned various quantities of the condensation product of lorol (1 mole) with from 0.25 to 3.0 moles of ethylene oxide. The mileage was found improved in each case, the magnitude of the improvement being essentially of the same order as indicated in the above examples.

The standard test hereinabove alluded to and by which the foam persistence of the compositions produced in the above examples was measured is as follows:

A. A standard greasy soil is prepared as follows:

A paste of the milk and flour is mixed thoroughly into a bletfl of the egg yolk and water. The India ink is added,=and then the mixture is blended with a melt of the peanut butter, lard and butter containing the printing ink. Finally, a solution of the salicylanilide in the ammonium hydroxide is added.

B. The detergent composition to be tested is made up into a solution containing 0.1 gm. of the active ingredient per liter of water. The solution is adjusted to a tempera- 4 ture of 2426 C., and 5 portions of the standard greasy soil are added successively, each followed by agitation for 2 minutes. This addition is continued until the foam formed fails to cover the surface of the liquid 30 seconds after agitation has been stopped.

The condensation products of lauryl alcohol (1 mole) with the respective quantities of ethylene oxide (0.25 to 3.0 moles) mentioned in the above examples can be prepared by conventional methods. For instance, they may be prepared simply by stirring a mixture of the two constituents in the indicated ratios at about 150 C.

in the presence of about 0.5 weight per cent of NaOH. For convenience, the ethylene oxide is introduced as consumed, keeping the pressure of the reaction vessel at a value not exceeding 15 lbs. gauge. These condensates are complex mixtures of various ether-alcohols and possibly some uncondensed alcohol. The quality of alcohol employed as initial material is not critical, technical grades (c. g., lorol) being suitable.

The incorporation of our novel adjuvants in the detergent may be done in a variety of optional methods, according to convenience. For instance, the adjuvant may be mechanically mixed with or kneaded into the solid detergent; or it may be crutched (mixed) into the detergent in the form of a slurry; or, again, it may be dissolved in an aqueous solution of the detergent. Furthermore, while such ready-for-use mixtures may be manufactured and may be preferable for many purposes, it is also within the scope of our invention to add the adjuvants mentioned to the aqueous cleansing bath prior to adding the detergent, or vice versa, or to add both the adjuvant and detergent simultaneously.

Mixtures of several types of the hereinabove indicated detergent compounds may be employed to produce a single detergent composition containing our novel adjuvant, and the customary builders may be added. Other permissible variations will be readily apparent to those skilled in the art.

We claim as our invention:

1. A composition of matter for cleansing greasy articles, comprising a detergent and an adjuvant, said detergent being a betaine compound selected from the group consisting of C-alkyl betaines and N-alkyl betaines whereof the said alkyl radicals contain from 10 to 16 C-atoms, and said adjuvant being the water-insoluble condensation product of 1 mole of dodecyl alcohol with substantially 1 mole of ethylene oxide, the quantity of adjuvant being not less than 10% by weight of said betaine compound and not greater than the quantity capable of being rendered water-soluble through the hydrotropic action of said betaine compound.

2. A composition of matter as in claim 1, the detergent being a compound of the formula wherein Alk designates a straight-chain alkyl radical of 10 to 16 C-atoms.

3. A composition of matter as in claim 1, the detergent being a compound of the formula References Cited in the file of this patent UNITED STATES PATENTS Downing et al Sept. 6, 1938 Schoeller et al. Iu1y'4, 1939 

1. A COMPOSITION OF MATTER FOR CLEANSING GREASY ARTICLES, COMPRISING A DETERGENT AND AN ADJUVANT, SAID DETERGENT BEING A BETAINE COMPOUND SELECTED FROM THE GROUP CONSISTING OF C-ALKYL BETAINES AND N-ALKYL BETAINES WHEREOF THE SAID ALKYL RADICALS CONTAIN FROM 10 TO 16 C-ATOMS, AND SAID ADJUVANT BEING THE WATER-INSOLUBLE CONDENSATION PRODUCT OF 1 MOLE OF DODECYL ALCOHOL OF ADJUVANT BEING 1 MOLE OF ETHYLENE OXIDE, THE QUANTITY OF ADJUVANT BEING NOT LESS THAN 10% BY WEIGHT OF SAID BETAINE COMPOUND AND NOT GREATER THAN THE QUANTITY CAPABLE OF BEING RENDERED WATER-SOLUBLE THROUGH THE HYDROTROPIC ACTION OF SAID BETAINE COMPOUND. 